Field of the Invention
The present invention relates to an electrophotographic apparatus and a process cartridge.
Description of the Related Art
As an electrophotographic photosensitive member to be mounted to an electrophotographic apparatus, there is known an electrophotographic photosensitive member containing an organic photoconductive material (organic electrophotographic photosensitive member). In an electrophotographic process, units such as a charging unit, an exposing unit, a cleaning unit, and a charge eliminating unit act on the electrophotographic photosensitive member.
The charging unit may employ methods such as charging using discharge, frictional charging, and injection charging, and the charging method using discharge is widely employed because of its excellence in charging uniformity. The charging method using discharge includes an abutment charging method in which a charging member is brought into abutment against an electrophotographic photosensitive member, and a non-abutment charging method in which a gap is secured between the charging member and the electrophotographic photosensitive member.
In the non-abutment charging method, the wear amounts of the charging member and the electrophotographic photosensitive member can be reduced, and adverse effects including toner contamination to the charging member can be reduced. For example, in Japanese Patent Application Laid-Open No. 2007-25725, there is disclosed a technology of securing a gap between the electrophotographic photosensitive member and the charging member.
Further, in the abutment charging method, the electrophotographic photosensitive member tends to be significantly affected by the discharge that occurs in the vicinity of the surface of the electrophotographic photosensitive member brought into abutment against the charging member to cause wear of the surface. In Japanese Patent Application Laid-Open No. 2005-300741, there is described a technology of setting an interval between an end position of the charging unit and an end position of a developing unit within 8 mm, to thereby suppress local wear of the surface of the electrophotographic photosensitive member.
Further, in Japanese Patent Application Laid-Open No. H01-277269, there is described an electrophotographic apparatus having an effective transferring width that is smaller than an effective charging width, to thereby suppress toner adhesion contamination of the transferring unit.
Further, in Japanese Patent Application Laid-Open No. 2005-172863, the following technology is described. A surface layer of the electrophotographic photosensitive member contains a compound cured through polymerization, and a contact charging member and a cleaning member are brought into abutment against the electrophotographic photosensitive member within an area where the surface layer is present. With this, local wear of the surface of the electrophotographic photosensitive member against which the end of the contact charging member is brought into abutment can be suppressed.
Further, in Japanese Patent Application Laid-Open No. 2005-114755, there is disclosed a technology of defining an opening width of a grid electrode (width of an area to be charged), a width of the electrophotographic photosensitive member, a width of a developing area, a width of a transferring area, and a width of a sheet powder removing area.